Stabilizing structure for wellhead equipment

ABSTRACT

A stabilizer for a wellhead is disclosed, comprising: a ground engaging support structure having lateral dimensions suitable for laterally stabilizing a wellhead; wellhead stabilizer elements disposed within the ground engaging support structure, the wellhead stabilizer elements having wellhead abutting faces spaced to laterally cage a wellhead to restrict lateral movement of the wellhead while permitting the wellhead to move in a vertical direction. A method of stabilizing a wellhead is also disclosed, the method comprising: assembling a ground engaging support structure around a wellhead, the ground engaging support structure having lateral dimensions suitable for laterally stabilizing the wellhead; and laterally spacing wellhead abutting faces at least partially around a circumference of the wellhead to laterally cage the wellhead to restrict lateral movement of the wellhead while permitting the wellhead to move in a vertical direction, the wellhead stabilizer elements being disposed within the ground engaging support structure.

TECHNICAL FIELD

This document relates to a stabilizing supporting structure or device for use with heavy equipment. More particularly, this document relates to a stabilizing device which is mountable around wellhead equipment and a wellhead so as to laterally stabilize the wellhead equipment and provide additional stability to the wellhead.

BACKGROUND

Snubbing units are known in the oil and gas industry for facilitating access to a well which is under pressure including, for example, during well operations such as well completions. A snubbing unit manipulates various tubular components in and out of a well while controlling the well under pressure. A typical snubbing unit operates with a blowout preventer (“BOP”) that has an annular element and pipe rams that will seal around the tubing while it is being pulled or lowered into the well.

A snubbing unit typically consists of a raised platform with two or more slip assemblies positioned above and beneath the platform. A typical prior art snubbing unit is disclosed in U.S. Pat. No. 4,085,796 to Council. Often the raised platform of the snubbing unit will include a railed work area or “basket” such as seen in U.S. Pat. No. 4,085,796. The two or more slip assemblies will be operated to run or pull tubulars as is well known in the art. Workmen will occupy the basket to assist in running or pulling the tubulars and will normally employ a power tong and a back-up tong in the basket to makeup or break apart a string of tubulars.

Often snubbing units are constructed to operate independently of a workover rig and are mounted on and supported solely from the wellhead structure. These independent units typically mount above a BOP, which in turn is mounted above the wellhead or casing bowl. Stabilization to such a unit may be provided by a variety of means, such as using wires or a platform, as shown in FIG. 1, with depending legs. Such platforms are commonly used in a variety of situations where stabilization is required. A difficulty with this device is that it is not readily adapted to large snubbing units.

SUMMARY

A stabilizer for a wellhead is disclosed, comprising: a ground engaging support structure having lateral dimensions suitable for laterally stabilizing a wellhead; wellhead stabilizer elements disposed within the ground engaging support structure, the wellhead stabilizer elements having wellhead abutting faces spaced to laterally cage a wellhead to restrict lateral movement of the wellhead while permitting the wellhead to move in a vertical direction.

A method of stabilizing a wellhead is also disclosed, the method comprising: assembling a ground engaging support structure around a wellhead, the ground engaging support structure having lateral dimensions suitable for laterally stabilizing the wellhead; and laterally spacing wellhead abutting faces at least partially around a circumference of the wellhead to laterally cage the wellhead to restrict lateral movement of the wellhead while permitting the wellhead to move in a vertical direction, the wellhead stabilizer elements being disposed within the ground engaging support structure.

A stabilizer for a wellhead is also disclosed, comprising: a ground engaging support structure having lateral dimensions suitable for laterally stabilizing a wellhead; wellhead stabilizer elements disposed within the ground engaging support structure, the wellhead stabilizer elements having wellhead abutting faces spaced to laterally cage a wellhead to restrict lateral movement of the wellhead, the wellhead abutting faces being laterally adjustable in separation.

A method of stabilizing a wellhead is also disclosed, the method comprising: assembling a ground engaging support structure around a wellhead, the ground engaging support structure having lateral dimensions suitable for laterally stabilizing the wellhead, the ground engaging support structure having laterally adjustable wellhead stabilizer elements disposed within the ground engaging support structure; and laterally adjusting the wellhead abutting faces to be spaced at least partially around a circumference of the wellhead to laterally cage the wellhead to restrict lateral movement of the wellhead.

These and other aspects of the device and method are set out in the claims, which are incorporated here by reference.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments will now be described with reference to the figures, in which like reference characters denote like elements, by way of example, and in which:

FIG. 1 is a perspective side view of a snubbing unit mounted atop a wellhead in a conventional fashion.

FIG. 2 is a side elevation view, in section, of a stabilizer for a wellhead in place laterally stabilizing a wellhead.

FIG. 3 is a side elevation view, in section, of another embodiment of a stabilizer.

FIGS. 4 and 4A are top plan views, in section, of a further embodiment of a stabilizer.

FIG. 5 is a side elevation view, in section of a further embodiment of a stabilizer.

FIGS. 6 and 6A are side elevation views, in section, of a further embodiment of a stabilizer.

FIG. 7 is a side elevation view, in section, of a further embodiment of a stabilizer.

FIG. 8 is a top plan view of the top portion of the frame of the stabilizer of FIG. 7.

FIG. 9 is a section view of the stabilizer, taken along the A-A section line of FIG. 8.

FIG. 10 is a section view of the stabilizer, taken along the B-B section line of FIG. 8.

FIG. 11 is a section view of the stabilizer, taken along the C-C section line of FIG. 8.

FIG. 12 is a top plan view of the bottom portion of the frame of the stabilizer of FIG. 7.

FIG. 13 is a top plan view of an attachment portion of the frame of FIG. 8 for mounting the wellhead stabilizer elements onto.

FIG. 14 is a top plan view of the wellhead stabilizer element attached to the embodiment of FIG. 8.

FIG. 15 is a section view of a wellhead stabilizer element, taken along the D-D section line of FIG. 14.

FIG. 16 is a flow diagram of a method of stabilizing a wellhead.

FIG. 17 is a flow diagram of a further method of stabilizing a wellhead.

FIG. 18 is a side elevation view, in section, of a set of blocks shaped to fit a wellhead connection.

DETAILED DESCRIPTION

Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims.

Referring to FIG. 2, a stabilizer 10 for a wellhead 12 is illustrated. Stabilizer 10 comprises a ground engaging support structure 14 having lateral dimensions suitable for laterally stabilizing the wellhead 12. Stabilizer 10 also comprises wellhead stabilizer elements 16 disposed within the ground engaging support structure 14. The wellhead stabilizer elements 16 have wellhead abutting faces 18 spaced to laterally cage wellhead 12 to restrict lateral movement of the wellhead 12. In some embodiments, faces 18 also permit the wellhead 12 to move in a vertical direction. It should be understood that faces 18 need not be directly in contact with wellhead 12 to perform the desired function.

Referring to FIG. 3, an embodiment of stabilizer 10 is illustrated in which the wellhead abutting faces 18 are laterally adjustable in separation, for example to fit different wellhead sizes. At least one wellhead abutting face 18 may be faced with a gripping surface, for example much like slip dies. Ghost lines are used to indicate the lateral adjustability of faces 18. Referring to FIG. 4, at least one wellhead stabilizer element 16 may be a plate 20, for example a C-plate, having an edge 22 that defines at least one wellhead abutting face 18. The elements 16 may be adjustable by a suitable mechanism, for example crank mechanisms, telescoping mechanisms, jacking mechanisms, locking bolt mechanisms, thread, screw, gear and pulley mechanisms. Referring to FIG. 3, a bolt 19 may be provided in association with each element 16 for selective entry into a series of slots (not shown) to lock element 16 in place. Referring to FIG. 4, an example of a geared track mechanism 24 is illustrated, with a handle 26 provided to adjust the spacing of face 18, for example using a worm gear (not shown) and screw 27. Other mechanisms of adjustment may be used, for example hydraulic or motor-driven mechanisms. It should be understood that the faces 18 may be locked in place once adjusted to the desired separation. As illustrated in FIG. 4, at least two, for example, three to ten or more, wellhead abutting faces 18 may oppose one another. The wellhead abutting faces 18 may be shaped, for example curved, to at least partially surround a circumference 28 of the wellhead 12. At least one wellhead abutting face 18 may be shaped with at least two radii of curvature to conform to multiple wellhead circumferences. By conforming at least partially to the lateral dimensions of the wellhead, better lateral stability may be achieved. Referring to FIG. 18, faces 18 may be defined by different size movable blocks, for example blocks 60 as illustrated. This way, stabilizer 10 may be used to laterally cage various parts of the wellhead, for example connections between wellhead components (as shown), blow-out-preventers, spools, and other suitable parts. The connection 66 illustrated is a spool 62-spool 64 connection.

Referring to FIGS. 4 and 5, the ground engaging support structure 14 may comprise a frame 30 and plural ground engaging legs 32 connected in support of the frame 30, for example through stance enhancer elements 39 (shown in FIG. 5) connected to frame 30. Referring to FIG. 5, the plural ground engaging legs 32 may be adjustable in height. This may be achieved using suitable mechanisms, for example at least one of spaced bolt holes 34 and a jacking mechanism 36. Hydraulic mechanisms (not shown) and the use of a motor may also be used. Legs 32 may also be adjustable laterally, using for example stance enhancer elements 39, in order to allow a user to position legs 32 in positions that suitably laterally support wellhead 12 more effectively. This is especially useful when stable ground is spaced at odd distances from the wellhead, and some adjustment of legs 32 is required. Legs 32 may be disposed around the periphery of the structure 14, in order to widen the stance and hence improve the lateral stability, of stabilizer 10. In some embodiments, structure 14 comprises a platform, for example a reinforced platform.

Referring to FIGS. 5 and 6, an embodiment of stabilizer 10 is illustrated. Referring to FIGS. 6 and 6A, wellhead stabilizer elements 16 may be adjusted into position by for example using a screw 42 mechanism, for example threaded into element 16. The screw 42 may be adjusted by turning a knob 43, screw 42 being anchored to frame 30, through for example a bracket 45. Adjustment may be facilitated by, for example at least one of gears, wheels, and tracks. Once faces 18 are in place, a locking mechanism may be used to secure the separation of faces 18.

Referring to FIG. 16, a method of stabilizing wellhead 10 is illustrated. Referring to FIG. 4, in a stage 100 (shown in FIG. 16), a ground engaging support structure 14 is assembled around a wellhead 12. The ground engaging support structure having lateral dimensions suitable for laterally stabilizing the wellhead 12. Referring to FIG. 4A, in a stage 102 (shown in FIG. 16), wellhead abutting faces 18 are laterally spaced at least partially around a circumference 28 of the wellhead 12, for example around a neck of a wellhead 12, to laterally cage the wellhead 12 to restrict lateral movement of the wellhead 12 while permitting the wellhead 12 to move in a vertical direction. The final positioning of faces 18 is illustrated in FIG. 4A, and may be illustrated in another embodiment by the ghost lines in FIG. 3 for example, or the embodiment of FIG. 6A. A rig may then be connected onto the wellhead 12, although in some embodiments, structure 14 may be assembled, for example by attachment of multiple pieces, around the wellhead with the rig, for example a snubbing unit, already in place.

Referring to FIG. 17, a further method of stabilizing wellhead 10 is illustrated. The method of FIG. 17 may be carried out similarly to the method of FIG. 16. Referring to FIG. 4, in a stage 104 (shown in FIG. 17), a ground engaging support structure 14 is assembled around a wellhead 12, structure 14 having laterally adjustable wellhead stabilizer elements 16. In a stage 106, the wellhead abutting faces 28 are laterally adjusted to be spaced at least partially around a circumference 28 of the wellhead 12 to laterally cage the wellhead 12 to restrict lateral movement of the wellhead 12.

In some embodiments, prior to, or as part of, laterally spacing elements 16, the wellhead stabilizer elements 16 may need to be attached to the ground engaging support structure 14. In these and other embodiments, at least a portion of elements 16 are removable. Referring to FIGS. 7-15, an example of this type of setup is illustrated. Referring to FIGS. 8, 9, and 14, elements 16 may be for example split plates that must be secured, for example by bolting through bolt holes 21, to structure 14, for further example to frame 30. This way, removable wellhead stabilizer elements 16 of various shapes may be interchanged to fit different wellhead 12 diameters. Referring to FIGS. 7 and 9, elements 16 may be attached to structure 14 using any suitable mechanism, for example by connection to a sunken flange 23 connected to frame 30. Referring to FIG. 13, flange 23 is illustrated in more detail, and may be provided as a plate for example welded to frame 30. Referring to FIGS. 14-15, exemplary elements 16 are illustrated. It should be understood that there may be more than two elements 16 provided. Faces 18 may be for example at least partially chamfered (shown by chamfers 25).

Referring to FIGS. 8-12, frame 30 may be composed of more than one element, for example a top portion 31 and a bottom portion 33. Referring to FIG. 8, top portion 31 is illustrated. Referring to FIG. 9, top portion 31 and bottom portion 33 may be reinforced by reinforcing members 49, for example walls. Referring to FIGS. 8 and 12, members 49 may be attachable to portions 31 and 33 via a suitable mechanism, for example slots 35 in the surface of each respective portion. Referring to FIGS. 8 and 11, members 49 may define channels 37 for stance enhancer elements 39 (shown in FIG. 7) to be positioned at least partially within. Referring to FIG. 8, the positioning of members 49 is indicated by ghost lines. Referring to FIG. 7, stance enhancer elements 39 may be allowed to move telescopically through channels 37, using for example rollers 40, in order to allow legs 32 to be effectively positioned in a sufficiently wide and stable stance. This also allows apparatus to be conveniently stowed in a stow position, for example with elements 39 fully retracted into channels 39, that is much smaller than a working position. Referring to FIG. 12, cutouts 41 for rollers (not shown) may be provided in at least one of portions 31 and 33 to facilitate the telescopic positioning/alignment of stance enhancer elements 39. Referring to FIG. 7, structure 14 may have guide holes 47 for attachment of guide lines to further stabilize the rig.

Wellhead 12 may include various wellhead components, include for example casing bowls, spools, blowout preventers, and other suitable components. An example of a spool may be an industry standard connection such as a 3000-10000 psi connection. It should be understood that the portion of wellhead 12 that is laterally caged need not be circular in cross-section, but may be a suitable geometry.

Stabilizer 10 is advantageous in that it laterally stabilizes a wellhead 12, including a rig connected to the wellhead. This is especially beneficial in windy conditions. Guylines may be used for additional support, although they are not required. Faces 18 collectively laterally stabilize the wellhead.

In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite article “a” before a claim feature does not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims. 

1. A stabilizer for a wellhead, comprising: a ground engaging support structure having lateral dimensions suitable for laterally stabilizing a wellhead; and wellhead stabilizer elements disposed within the ground engaging support structure, the wellhead stabilizer elements having wellhead abutting faces spaced to laterally cage a wellhead to restrict lateral movement of the wellhead while permitting the wellhead to move in a vertical direction.
 2. The stabilizer of claim 1, in which the wellhead abutting faces are laterally adjustable in separation to fit different wellhead circumferences.
 3. The stabilizer of claim 1 in which the wellhead abutting faces are shaped to at least partially surround a circumference of the wellhead.
 4. A method of stabilizing a wellhead, the method comprising: assembling a ground engaging support structure around a wellhead, the ground engaging support structure having lateral dimensions suitable for laterally stabilizing the wellhead; and laterally spacing wellhead abutting faces at least partially around a circumference of the wellhead to laterally cage the wellhead to restrict lateral movement of the wellhead while permitting the wellhead to move in a vertical direction, the wellhead stabilizer elements being disposed within the ground engaging support structure.
 5. A stabilizer for a wellhead, comprising: a ground engaging support structure having lateral dimensions suitable for laterally stabilizing a wellhead; and wellhead stabilizer elements disposed within the ground engaging support structure, the wellhead stabilizer elements having wellhead abutting faces spaced to laterally cage a wellhead to restrict lateral movement of the wellhead, the wellhead abutting faces being laterally adjustable in separation.
 6. The stabilizer of claim 5, in which at least one wellhead abutting face is faced with a gripping surface.
 7. A method of stabilizing a wellhead, the method comprising: assembling a ground engaging support structure around a wellhead, the ground engaging support structure having lateral dimensions suitable for laterally stabilizing the wellhead, the ground engaging support structure having laterally adjustable wellhead stabilizer elements disposed within the ground engaging support structure; and laterally adjusting the wellhead abutting faces to be spaced at least partially around a circumference of the wellhead to laterally cage the wellhead to restrict lateral movement of the wellhead.
 8. The stabilizer of claim 2 in which the wellhead abutting faces are shaped to at least partially surround a circumference of the wellhead. 